Feeding mechanism for rock drills



EVAL 2,221,118

Nov. 12, 1940,

W. A. SM|THJR.,

FEEDING MECHANISM FOR ROCK DRILLS 2 Sheets-Sheet l Filed Dec. 2, 1958 ETAL 2,221,118

Nov. 12, 1940.

W. A. SMITH, JR.,

FEEDING MECHANISM FOR ROCK DRILLS 2 Sheets-Sheet 2 Fler Dec. 2, 1958 mx .KW .Q N MQ .MW Y -Y QQ v ...www n..

mm .T.. W6

Patented Nov. 12, 1940v NETE@ STATES PATENT OFFICE FEEDING MECHANISM FOR ROCK DRILLS Application December 2, 1938, Serial No. 243,612

2 Claims.

This invention relates broadly to rock drills, but more particularly to an improved feeding mechanism for a rock drill of the drifter type.

One object of this invention is to provide a rock drill with a iiuid actuated feeding motor of the rotary type constructed and arranged in a manner forming a simple and compact assembly.

Another object of this invention is to produce an improved uid actuated rotary motor provided with self contained rotation speed reducing means of simple and eilicient construction.

Another object of this invention is to provide a rock drill equipped with an automatic feeding 5 mechanism carried by the drill for slidable movement therewith, with improved remote feed control means preferably operable from the rear end of the shell supporting the drill.

Other objects and advantages more or less an- 20 cillary to the foregoing reside in the specific construction and aggroupment of the elements peculiar to this structure, as will become apparent from a more complete examination of this specication.

In the drawings:

Fig. 1`is a side elevational view, partly in section, of a rock drill embodying the invention.

Fig. .2 is an enlarged end elevational view of the rock drill looking in the direction of the arrows 30 2*-2 in Fig. 1.

Fig. 3 is an enlarged cross sectional view taken in a plane indicated by line 3-3 in Fig. 1.

Fig. 4 is an enlarged cross sectional view taken' in a plane indicated by line 4 4 1n Fig.1.

Fig. 5 is a view similar to Fig. 4 but taken in a plane indicated by line 5-5 in Fig. 1.

Fig. 6 is an enlarged cross sectional view taken in a plane indicated by line 6-6 in Fig. 1.

Figs. 7 to 10 inclusive are enlarged cross sec- 40 tional views taken in a plane 'indicated by line 1-1 in Fig. 1 and showing the valve in diierent positions.

Figs. 11 to 14 inclusive are enlarged cross sectional views taken in a plane indicated by line 45 II--Il in Fig. 1 `showing the position of the valve corresponding to that shown in Figs. '7 and 10 respectively.

Fig. 15 is an enlarged longitudinal sectional view taken in a plane indicated by line I5--I5 in 50 Fig. 8, while Fig. 16 is a view similar to Fig. 15 showing some of the movable parts in a different position.

Referring to the drawings, 28 represents a fluid actuated rock drill or drilling motor having a. 55 iiuid actuated vpiston (not shown) reciprocable therein for delivering impacts to a drill steel 2l. The drilling motor is slidable on a support or shell 22 having welded to the right end thereof in Fig. 1, hereinafter referred to as the rear end of the apparatus, a handle 23 to which is secured by a key 24 and nut 25, a stationary feed screw 26, which screw extends longitudinally from one to the other end of the shell 22.

A feed motor housing 21 is secured to the drilling motor 28 by side bolts 28, thereby causing the housing 21 to form a part of the drilling motor slidable therewith on the support 22. This housing accommodates a transversally disposed throttle valve rotatable through a handle 29, and having motive fluid admitted therein via a connection 30, which connection also supplies motive uid to ports 3l independently of the throttle valve. Theports 3l lead into a pocket 32 formed within a plate 33 rigidly secured within the housing 21. From the pocket 32 the motive fluid is free to flow through a passageway 34 into the rear end of a longitudinally disposed bore 35 provided within a housing 36 which forms a cover for the housing 21. Rotatable Within the bore 35, there is a feed control or valve 31, the purpose of which will be explained later.

Secured within the housing 21 by a pin i8, there is a stator I8 provided with a cylindrical chamber 38 closed at one end by the plate 33 and at the other end, by a similar bearingplate 39. Extending longitudinally through the chamber 38, in eccentric relation with the center axis thereof, there is a shaft generally designated by 40, which shaft is formed of two portions, one, the portion 4I being rigidly secured against rotation in the plate 33 by a key 42, While the other portion 43 is a rotatable portion having one end journaled within the adjacent end of the stationary portion 4|, while the other end is journaled within a ball bearing 44'.

Rotatable within the chamber 38 of the stator I9, there is a rotor 44 operatively supported by the shaft 40. 'I'his rotor carries the usual vanes 45 radially slidable in operative engagement with the inner wall oi the chamber 38. Internally the rotor 44 is adequately machined to fit on the shaft 40, and is provided, intermediate its ends, with an enlarged central cavity 46 accommodating two gears 41 and 48, the gear 41 being formed on the inner end of the shaft stationary portion 4I, while the gear 48 is similarly provided on the inner end of the shaft rotatable portion 43. The rotor 44 is also formed with two diametrically opposed cavities 48-49 which are parallel to the center axis of the cavity 46 and open thereinto as shown in Figs. 4 and. 5. Within each of the cavities 48, there is iournaled within adequate bearings a spindle 88 formed with two gears or pinions 5| and 82, the pinions 5| meshing with the gear 41, while the pinions 52 mesh with the gear 48. To facilitate assembly the rotor 44 includes a removable disc 53 closing the normally open ends of the cavities 48.

'I'he rotatable portion 43 of the shaft 48 extends from the rotor 44 into the casing 21 where it carries a gear 54 secured thereon by a key 54', which gear meshes with an idler 55 rotatable on a stationary shaft 56.

Rotatable on the stationary feed screw 28, there is a rotatable feed nut 51 operatively carried by the housing 21 against axial movement relative thereto, and formed with a gear 58 meshing with the idler 88.

Adjacent a bore within which is rotatably mounted a valve 31, there is a parallel bore 58 having pressed therein a bushing 88, which bushing is formed with a partition 8| having ports 82 extending therethrough affording communication between the inner portion 83 of the bushing with the outer portion 84 thereof. Slidable within the inner portion 83, there is a small valve or governor 85 formed witha neck 88 and a head 61, which head has a tip 88 engageable with 'the partition 8|.- Adjacent the partition 8|, the inner portion 83 of the bushing 88 is slightly enlarged as at 68 to provide an annular clearance between the head 81 of the governor 85 and the inner wall of the bushing 88. A compression spring 18 constantly urges the governor 88 into engagement with the partition 8i. Adjacent the neck B3, the bore 48 is provided with an annular groove 1| in constant communication Vwith the interior of the bushing 88 through a port 12 and with the bore 35 through a port 1S.

From the outer end portion of the bushing 88, motive uid is free to ow into a pocket 16 formed within the plate 38, and` therefrom into the chamber 38 of the stator I8 through a port 15 and groove 18.

The valve 31 rotatable within the bore 35 is formed with a central bore 11 and with a radial port 18 capable of communication with the port 13 leading to the governor 88. Within the vertical plane passing through the port 18, the valve 31 is also provided with a semicircular groove 18 in constant communication with an exhaust port 88. In the same vertical plane, the housing 38 is provided with a passageway 8| -leading from the valve 31 into the pocket 14 provided within the plate 38.

Within another vertical plane. the valve 31 is provided with another radial port 82 and a semicircular groove 83, the port 82 being capable of communication with a passageway 84 which leads into a pocket 85 within-the plate 33, from where uid may be admitted into the rotor chamber 38 via a port 85 and groove 81, while the semiannular groove 83 is in constant communication with an exhaust port 88. From the stator chamber 38, the motive uid may exhaust to the atmosphere through exhaust ports I1.

Below the feed screw 28, the support 22 carries a rotatable rod 88 extending longitudinally thereof with one end protruding through the rear end of the support to receive a handle 88 secured on the rod by a key 8| and a nut 82. Slidable on the rod 88, there is a sheave 83 mounted thereon against relative rotation by means vof a flat 84 extending the full length of the rod. This sheave is connected to the front end of the valve thereby causing the sheave, upon slidable movement of the drilling motor 28`on the support 22 to slide on the rod 88. In order to prevent accidental rotation of the valve 31, it is provided with peripherallydisposed serrations 88 frictionally engaged by a spring pressed plunger 88 slidable within a bore |88, which bore is closed by a plug III.

In the operation of the apparatus, when motive fluid is admitted into the throttle valve (not 20 shown) through the connection 38, it will also flow through the passageways 3| into the pocket 32 and therefrom into the rear end of the bore 35 through the passageway 34. In the position of the valve 31 shown in Figs. '1 and 11, admission of the motive fluid into the stator I8 is prevented by the valve closing the ports 13, 8| and 84, thereby preventing operation of the feed motor.

' When it is desired to feed the drilling motor rapidly to the work, the valve 31 may be positioned as shown in Figs. 9 and 13. In this instance motive fluid from the rear end of the bore 35. will flow through the valve center port 11 and therefrom into the pocket 14 via the passageway 8|. From the pocket 14 it will be admitted into' the stator chamber 38 through the passageway 15 and the groove 18, thereby acting on the vanes 45 for effecting rotation of the rotor 44 in a counterclockwise direction in Fi .A and 5, and the Aconsequential rotation of e pinions 8| around the stationary gear 81 in the same direction, thus resulting in the axial rotation of the pinions 52 in a counterclockwise direction in Fig. 5, which rotation will cause the gearfli to rotate in a clockwise direction in Fig. 5. The rotation of the gear 48 which forms a part of the rotatable portion 43 of the shaft it will of course be transmitted to gear 88 keyed on the portion 48, which rotation will in turn be transmitted to the gear 58 through the idler 58, thereby causing rotation of the feed nut 51 in a clockwise direction in Fig. 8, and the consequential forward feeding motion of the drilling motor 28 due to the operative engagement of the nut 51 with the'stationary feed screw 28.

From the stator chamber 38, motive fluid is free to exhaust in the usual manner through the exhaust ports I1 which are diametrically opposed to the contacting point of the rotor 44 with the inner wall pf the chamber 38. Any amount of motive fluid remaining within the chamber 38 between the groove 81 and the exhaust ports I1, will be free to exhaust via the v groove 81, the port 88, the pocket 88, the passageway 84, the valve groove 83 and exhaust port 88.

Once'the drill steel 2| is in contact with the work, the operator will rotate the valve 31 into the position shown in Figs. 8 andl 12. In this instance, the motive fluid instead of being directly admitted into the stator chamber 38, will iiow therein via the governor 88. As shown in Fig. 8, the port 18 is in communication with the port 13 leading into the bushing 88 through the groove 1| and the port 12. From the inner portion 83 of the bushing 88, the motive nuidwill ow over the head 81 of the governor 85 into the upper portion 84 of the bushing 68 via the ports 82. From the portion 84, the iiuld is admitted into the pocket 14, from where it is free to flow into the stator chamber 88 via the passageway' 15 and the groove 16 for acting on the vanes 48 to cause rotation of the rotor 44 as above described. In this instance when the rotor 44 is operating under normal load, the motive fluid from the valve 31 will flow freely into the upper portion 64 of the sleeve. 88 around the head 81 of the-governor 85. However, when the drilling motor 28 is fed to the work at a faster rate of speed than that of the cutting speed of the drill 18 steel 2|, the drill steel being forced in contact with the work will subject the rotor 44 to an abnormal load which will cause an increase of the pressure of the motive iiuid admitted into the stator chamber 38, which additional pressure 20 will act on the head 81 of the governor 88 for shifting it into the position show n in Fig. 16. In this position of the governor, the free flow of the motive uid into the upper portion 84 of the bushing 88 is prevented by the governor head 81 28 engaging the inner wall of the bushing, thereby momentarily preventing actuation of the rotor 44 and enabling the drill steel 2| to penetrate the work suiiiciently to remove the additional load to which the rotor 44 Vwas subjected. There- 88 after the governor urged by the action of the compression spring 18 will again be shifted into theposition shown in Fig. 15 to enable a free iiow of the motive uid into the stator chamber 88, and the consequential normal operation of 38 the feed motor. i

During the forward feeding motion of the drilling motor 28 controlled by the governor 85, that v is, with the valve 81 in the position shown in Fig. 8, the exhaust of the motive fluid from the n stator chamber 88 will take place as above described, namely, through the exhaust ports i1 and through the groove 81, passageway 88, pockets 88, passageway 84, the valve groove 83 Iand exhaust Port 88.

When it is desired to feed the drilling motor away from the work, the valve 81 may be positioned as shown in Figs. 18 and 14. In this instance the motive fluid from the valve center bore 11 will iiow into the pocket 88 via the valve port o 82 and the passageway 84. From the pocket 88, the motive iiuid is free to flow into the stator chamber 8 8 through the passageway 88 and the groove 81, thereafter acting on the vanes 48 for imparting rotation to the rotor 44 in a clockwise n direction in Fig. 4, and the consequential rotation of the pinions 8| around the stationary gear 41 in the same direction resulting in the clockwise axial rotation of the pinions 8| and 82, which last rotation is transmitted to the gears 48 and 84 in a ,o clockwise direction. From the gear 84 rotation in the same direction will be transmitted to the feed nut 81 through the idler 88, causing rearward feeding motion of the drill motor 28 due to the operative engagement of the feed nut 81 with the stationary screw 28. In this instance, the motive :duid after acting on the vanes 48 is free to exhaust through the exhaust ports l1, and

finally through the groove 18, the passageway` 18, the pocket 14, the passageway 8|, the valve 7 groove 18 and the exhaust port 88.

Rotation of the valve 81 may be effected from the rear end of the support 22 by the operator rotating the handle 88 rigidly secured on the rod 88. thereby transmitting rotation to the rod u whichisinturntransmlttedtothevalve by the flexible strip 95. `The drilling motor 28 sliding on the shell 22 will carry therewith the sheave .93 and the flexible strip 95. while the rod control handle 88 remains 'at the rear end of the shell, thereby'enabiing control of the feed motor from I the rear end of the shell irrespective of the yposition lof the drilling and feed motors on the shell.

From the foregoing description, it will be understood that-rapid forward feeding motion of the drilling motor 28 may be obtained by posi- 18 tioning the valve 31 as shown in Figs. 9 and 13, in which instance the motive iiuid isdirectly admitted into the feed motor without passing through the governor 88. After the drill steel 2| is in contact with the work, in order to auto- 15 matically control the feeding speed of the drilling motor in a manner proportional to the drilling speed of the drill steel 2|, the valve 81 maybe positioned as shown. in Figs. 8 and 12, thereby causing admission of the motive fluid to the feed 20 motor to be controlled by the governor 85. When it is desired to feed the drilling motor away from the work, the valve 81 may simply be positioned as shown in Figs. 18 and 14.

In the improved feeding motor above described. the novel transmission mechanism incorporated within the rotor 44 affords an efficient rotation speed reducing mechanism between the rotor'and the feed nut 81, through which mechanism rotation is transmitted to the feed nut 81 at a greater 3 rate of power than that of the rotor 44. The speed reduction between the rotor 44 and they drive shaft 48 may be varied at will by changing the pitch diameter of the several gears and pinions involved in this mechanism. For instance, i by making the gear 48 larger than the stationary gear 41 and the pinions 82 smaller than the pinions 8l, it will be possible to obtain a greater speed reduction than that possible with the gears 41 and 48 having equal pitch diameter. 40

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive o'r confining and it is to be further 45 understood that various rearrangements of parts and modications of structuraly'detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

1 claim: 5

1. In an apparatus of the class described, a support, a reversible fluid actuated rotary motor slidable on said support, a valve carried by 'said motor capable of rotation for controlling the direction of rotation of said motor, a rotatable rod extending longitudinally of the support, a sheave slidable. on said rod against rotation relative thereto, and a flexible strip passing over said valve and sheave for transmitting rotation from said rod to said valve irrespective of the position so of said motor on the support.

2. In an apparatus of the class described, a support, a drilling motor slidable on the support,

a rotatable member carried by the motor for slidablemovementtherewith, a rotatable rod extending longitudinally of the support, a sheave slidable on said rod against rotation relative thereto, and a flexible connection between said member and sheave effective for transmitting the rotation of said rod to said member irrespective of the position of said motor on the support.

wnmm A. smrn. Jn. ALBERT r'mocn'r. 7, 

